Nicklaus hit about 15 practice balls at the TPC at Dearborn in Michigan before pain forced him to stop.
He withdrew from the morning pro-am after only playing about three holes. He then spoke at length during a press conference and talked encouragingly about his health, prior to reaching the practice range.
Im the best Ive been for a long time right now, or I was before I teed off this morning, he said.
The 62-year-old said he was pleased with his play in a nine-hole practice round with friends and family Tuesday at Muirfield Village.
I thought after playing yesterday, Boy, I am ready to play. I am ready to go. I woke this morning and I couldnt stand on my right side to save my life.
I just dont like to be in the position of keeping somebody out of the tournament, he added. Would I like to play? Youre darn right Id like to play.
Nicklaus withdrew from this event last year due to a back problem, and has since competed in only three tournaments.
Nicklaus won 70 events on the PGA Tour, and has compiled 10 victories on the Senior circuit, though none since 1996. He has won this event once, in 1990.
Full coverage of the Ford Senior Players Championship